Liquid fuel injection pumps



Aug. 23, 1966 w, cL ToN 3,267,863

LIQUID FUEL INJECTION PUMPS Filed March 13. 1964 United States Patent LIQUID FUEL INJECTION PUMPS William L. Clifton, Churchdown, England, assignor to Bryce Berger Limited, Gloucester, England Filed Mar. 13, 1964, Ser. No. 351,619 Claims priority, application Great Britain, Mar. 14, 1963, 10,097/ 63 1 Claim. (Cl. 10341) This invention relates to liquid fuel injection pumps for internal combustion engines, and of the kind comprising in combination a bodypart, a reciprocable pumping plunger in the body part, an externally toothed sleeve, a longitudinally movable control rod having teeth meshing with the teeth of the sleeve, and means whereby angular movement of the sleeve will be imparted to the plunger to vary the quantity of fuel delivered by the pump.

During the assembly and re-assembly of such pumps it is often difficult to ensure that the teeth of the sleeve engage with the teeth of the control rod in the correct relationship, and the object of the present invention is to provide convenient means whereby this engagement can be more readily effected.

According to the invention the control rod is located within the body part of a detachable cover, and there is provided in the toothed portion of the control rod and the toothed part of the sleeve respectively a pair of holes which can be aligned when their respective teeth are correctly interengaged, the arrangement being such that when the cover is removed the teeth of the control bar can quickly be engaged correctly with the teeth of the sleeve by inserting a wire or pin through the hole in the rod into the hole in the sleeve, and then moving the rod along the wire or pin until the teeth are engaged.

In the accompanying drawing there is illustrated a known form of fuel injection pump which comprises a body part 1 in which is mounted a pump body 2. Within the pump body is formed a cylindrical bore 3 which ac commodates a reciprocable pumping plunger 4. The plunger is provided with an abutment plate 5 at its outer end and located between the plate 5 and the body part 1 is a coiled compression spring 6 which urges the plunger towards the outer end of the bore.

The plunger is arranged to be moved inwardly, against the action of the spring, by an engine driven cam (not shown) which bears against a cup shaped follower 7 slidably mounted in the body part. Furthermore during the inward movement of the plunger fuel is discharged from the inner end of the bore 3 to an outlet 8 via a spring loaded non-return valve9. The outlet 8 is arranged to be connected, in use, to an engine cylinder so that as the plunger is moved inwardly fuel will be delivered to the engine.

Moreover in the inner end portion of the periphery of the plunger is a helical or other shaped groove 10 which can register with a spill port 11 extending through a pump body 2 into an annular chamber 12 defined in the body part and to which fuel is delivered from a source of fuel under pressure through a pair of inlets 13. The arrangement is such that when the spill port 11 is uncovered by the groove 10 during inward movement of the plunger fuel will be spilled from the inner end of the 3,267,863 Patented August 23, 1966 bore and the delivery of fuel to the engine will cease. During the outward movement of the plunger when the spill port is uncovered by the inner end of the plunger fuel will flow into the inner end of the bore from the annular chamber ready for the next inward movement of the plunger.

The plunger 4 is connected by a peg 16 to an extending toothed and co-axial sleeve 14 which is movable angularly about its axis by means of a control rod 15 movable axially at right angles to the axis of the sleeve, the rod being provided with rack teeth meshing with the sleeve. The rod is slidable within a guideway 17 in the body part, and is retained within the guideway by means of a detachable cover 18.

In applying the invention to such a pump there is formed in the toothed portion of the control rod 15 a hole 15a which can be brought into register with a hole 14a in the sleeve when the control rod and sleeve are meshing in the correct relationship. These two holes serve to facilitate assembly and re-assem'bly of the pump which is effected by inserting a wire or pin through the hole 15a in the control rod, and then into the hole 14a in the sleeve. The control rod is then slid along the wire or pin until its teeth engage the teeth of the sleeve thereby ensuring the correct relationship of the teeth. Subsequently, the wire or pin is withdrawn, and the cover 18 is attached to the body part to hold the teeth in mesh.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

A liquid fuel injection pump comprising in combination, a body part, a reciprocable pumping plunger mounted within the body part, a sleeve surrounding said plunger, means interconnecting the sleeve and plunger so that angular movement of the sleeve will result in angular movement of the plunger, a plurality of teeth formed on the outer periphery of the sleeve, a toothed control rod slidable in the body part the teeth of the control rod being engageable with the teeth of the sleeve, the control rod and sleeve having apertures formed therein and into which a rod or wire can be inserted so as to guide the engagement of the teeth of the rod with the teeth of the sleeve during assembly of the rod to the body part, and a cover which can be secured to the body part to retain the control rod therein after the engagement of the teeth of the sleeve and the teeth of the rod have been effected.

References Cited by the Examiner UNITED STATES PATENTS 2,670,684 3/1954 Fagerholt. 2,700,342 l/ 1955 French. 2,922,369 1/ 1960 Nystrom 103154 3,004,496 10/ 1961 Minett 103-154 FOREIGN PATENTS 1,317,076 12/1962 France.

645,262 8/ 1935 Germany. 1,035,404 7/ 1958 Germany.

636,351 4/ 1950 Great Britain. 403,026 4/ 1943 Italy.

MARK NEWMAN, Primary Examiner.

W. J. KRAUSS, Assistant Examiner. 

